The Massachusetts General Hospital has long been a pioneer in the development and application of PET technology to problems of biomedical importance. The MGH PET imaging program is actively supported by NIH-funded research addressing questions of fundamental importance in fields of experimental pharmacology, tumor biology, molecular imaging, and cognitive neuroscience. The current PET facilities at the MGH clinical campus have limited growth potential for research activity given the increasing clinical demands and the age of the equipments. The MGH PET imaging effort has had great success in translating recent scientific developments from the bench to the bedside. The use of PET imaging to address specific patient related clinical questions has risen dramatically, especially in the areas of oncology, neurology and cardiology. As a result of growing awareness of the clinical impact of PET on patient care, clinical demands on the existing MGH PET facility on the hospital campus are escalating. The facility is utilized near capacity and simply will be unable to keep pace with growing research demands of the scope possible on the research campus. The greatly increasing need for PET to support an expanding range of research applications simply cannot be met within the constraints of the already overburdened PET facilities at the main campus. Initially, the PET imaging facility in Charlestown will have two imaging devices located at the Martinos Center. The first, the HRRT-PET camera will be installed in a few months. The second is a Concord microPET system for animal imaging. This system is already operating in a temporary laboratory on the main campus and will be transferred to the Charlestown facility after the cyclotron is working. The MGH has committed to install it by 2007. It is expected that additional imaging instruments will be added as the program grows. Funding of the currently proposed F-18 synthesizer will provide a critical component in our plan to synthesize radioligands for the HRRT-PET system. In addition, there is an increasing demand of F-18 labeled radiopharmaceuticals in preclinical animal studies conducted with the microPET imager. Given the exceptional biomedical imaging research community co-located at the MGH research campus, the broad multi-modality imaging resources of the Martinos Center, the critically overburdened state of the existing MGH clinical campus PET facilities, and the existing technical expertise and infrastructure in place, the proposed F-18 synthesizer resource would immediately increase the efficiency, accessibility, and innovation of research programs, and complete the MGH's strategy to provide an integrated biomedical imaging research environment. The proposed fluorine-18 synthesizer has the highest performance of the commercial systems currently available for production fluorine-18 labeled radiopharmaceuticals. The synthesizer must balance a number of factors in the design to fulfill requirements for performance, accessibility and fitness to the research environment. [unreadable] [unreadable] [unreadable]